1. Field of the Invention
The present invention relates to a system and article of manufacture for establishing and requesting status on a computational resource.
2. Description of the Related Art
Computing systems often include one or more host computers (“hosts”) for processing data and running application programs, direct access storage devices (DASDs) for storing data, and a storage controller for controlling the transfer of data between the hosts and the DASD. In operating systems that conform to the International Business Machines Corporation (“IBM”) Enterprise Systems Architecture (ESA) 360, 370, and 390 architectures, the storage controller, also referred to as a control unit or storage director, manages access to a storage space comprised of numerous hard disk drives connected in a loop architecture, otherwise referred to as a Direct Access Storage Device (DASD).
Hosts may communicate with the storage controller through logical paths also referred to as host channels, where there may be one or more logical paths for each physical communication path between a host port and storage controller port. Both the host and the storage controller must maintain a consistent view of their logical paths to avoid communication errors. However, situations may arise where the host and storage controller views of the logical paths differ. In such situations, the host may issue an Input/Output (I/O) request down a channel or logical path that the host believes exists, but that the storage controller does not recognize. In such case, an interface controller error would occur due to this inconsistent view of the logical path states between the controller and host.
For these reasons, there is a need in the art to provide techniques for ensuring that the host and storage controller maintain a consistent view of logical paths therebetween to avoid communication errors that result from inconsistent views.